Posui custodem super ea
by unlikely2
Summary: Do not mess with the new Potions Master's store cupboard.


_Young teacher, the subject_  
_Of schoolgirl fantasy_

.

Not this one.

"Saturnine" might have been the kindest description. Scrawny, dark eyed, unkempt. Not a happy bunny. Don't even mention what they _had_ called him.

Not that long ago, either.

The other Heads of House tried to support him. Dumbledore . . . not so much. Slytherin House was still waiting. Waiting now to see what he'd do about the continuing thefts from the potions supply cupboard. Severus Snape took a deep breath and considered his options.

He could keep an eye on things in the classroom. But not whilst doing rounds. Or sleeping. (He'd been forbidden from sleeping in his private lab which opened onto the other end of the storeroom). His request for the services of a house elf had been refused and the Dark Arts were right out.

Time, it would seem, for a different approach.

Next morning, there was a new lock upon the door. Large, grey painted and screwed to the interior of the door with a small hole cut through to allow the key to be used from the outside, no one was impressed by it. The more observant amongst the students however noted that there was also something chalked onto the frame above the door. "POSUI CUSTODEM SUPER EA" or for the less linguistically inclined, 'I have placed a guardian over it".

By midday speculation abounded.

By mid afternoon there was mention (amongst muggleborns) of a medievalist scholar named Montague Rhodes James, his story entitled "The Treasure of Abbot Thomas" and what became of the person who found it. By evening, there was also general agreement throughout much of the school that the current Head of Slytherin was "Definitely the Type" and, consequently, a degree of circumspection if not quite terror.

The next morning Snape found himself being invited to the Headmaster's Office to explain himself. 'Actually, I'm on my way to the Hospital Wing. Madame Pomfrey has again requested my assistance,' he told the face in the flue politely. 'Perhaps we could meet up there?'

Hogwarts' youngest Potions Master ever found himself being escorted from the school in chains.

Some hours later he returned, under Auror escort, at the head of a small team from Saint Mungo's, his expertise being required to diagnose and (it was hoped) treat a potions mishap suffered by students who, having got into the supply cupboard, had encountered something unexpected and could now not be dissuaded from hopping, bouncing and flapping weightlessly around the hospital wing (all the while screaming), by any means save deep unconsciousness.

. . .

.

Light from the classroom glinted off broken glass: some smaller pieces on the floor but most on the ceramic draining board of a large sink that stood opposite the door.

'So,' breathed Moody, (who had been evicted from the hospital wing), 'no one's touched anything?'

'Vanished the spillage,' replied Shacklebolt. 'Took note of what was written on the broken containers. Left them in situ. "Lumos maxima!'' The Aurors blinked and looked around the cupboard.

'Tidy,' commented Shacklebolt.'

'The stuff on the sink?' demanded Moody.

'Spoiled and contaminated potions ingredients. According to Snape, some of the students have a habit of switching labels, even containers to make it harder to tell what's missing. He was waiting for Dumbledore to get back to him before disposing of them.'

'Contaminated,' muttered Moody.' Could have been any bloody thing.'

'That's why Saint Mungo's are having so much trouble,' said Shacklebolt but Moody, eye rolling in all directions, wasn't listening. The younger Auror opened the other door to the cupboard to disclose a small laboratory, also scrupulously clean, with a cot set up along one wall.

'Alarm spell between the lock and the door,' announced Moody. 'Someone tries to open it using magic, it'll scream like a banshee.'

'So how did they get in?'

'Using the key of course. Out you go.' Moody shoved Shacklebolt into the classroom and locked the door behind him. 'Now, open the door.'

After a while, Moody took a small book from a pocket and began to make notes.

_'Depulso!'_ snapped Shacklebolt from outside the door. The key shot from the lock and across the room to rattle with the broken glass on the draining board. _"Accio key!"_ The item in question bounced off the door and clattered on the floor. A second _"Accio key!"_ took it out under the door.

Looking somewhat sheepish, Shacklebolt let himself back in.

. . .

.

A small, rather greenish, coterie of students watched as a somewhat battered and extremely belligerent individual laid hand on their potions professor.

_"Depulso"_ pushes the key out of the lock and _"Accio"_ gets it back under the door. Then open normally. How was a muggle lock going to stop anyone with even the slightest bit of intelligence?'

Snape could not have agreed more. Indeed, that had been the point. 'It is still,' he pointed out, 'more than was there before. My concerns regarding students poisoning themselves, and each other, as well as the security of the cupboard are all on record, as is a refusal to countenance stronger measures. Perhaps if you were to try addressing your concerns to the Headmaster?'

Madam Pomfrey, not unexpectedly, agreed with him (quite forcefully) until the Aurors decided to take matters elsewhere.

Years later, school lore still maintains that Snape has set some kind of Guardian over his domain. Off course, some students will believe anything they're told while there are others that are oblivious. Every school gives rise to its own mythology but this is not just any school - this is Hogwarts School of Witchcraft and Wizardry. Here, words have power. Belief can change things, summon things, even call things into being.

. . .

.

Perhaps this was the beginning.

.

* * *

A new and, I hope, better version of 'The Guardian'.


End file.
